package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 */
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {
    @Resource
    private ISeckillVoucherService iSeckillVoucherService;
    @Resource
    private RedisIdWorker redisIdWorker;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private RedissonClient redissonClient;

    // 阻塞队列
    //private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);
    // 线程池
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();
    // 初始化任务
    @PostConstruct
    private void init() {
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    // 获取消息队列中的信息
    private class VoucherOrderHandler implements Runnable{
        String queueName = "streams.orders";
        @Override
        public void run() {
            while (true) {
                try {
                    // 1、获取消息队列中的订单信息 XREADGROUP group g1 c1 COUNT 1 BLOCK 2000 STREAMS streams.order >
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    // 2、判断消息是否获取成功
                    if (list == null || list.isEmpty()) {
                        // 2.1 如果获取失败，说明没有消息，继续下一次循环
                        continue;
                    }
                    // 3、解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    // 4、 如果获取成功，可以下单
                    handleVoucherOrder(voucherOrder);
                    // 5、ACK确认 SACK streams.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());

                } catch (Exception e) {
                    log.error("处理订单异常",e);
                    handlePendingList();
                }
            }
        }
        private void handlePendingList() {
            while (true) {
                try {
                    // 1、获取pending-list中的订单信息 XREADGROUP group g1 c1 COUNT 1  STREAMS streams.order 0
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    // 2、判断消息是否获取成功
                    if (list == null || list.isEmpty()) {
                        // 2.1 如果获取失败，说明pending-list没有异常消息，结束循环
                        break;
                    }
                    // 3、解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    // 4、 如果获取成功，可以下单
                    handleVoucherOrder(voucherOrder);
                    // 5、ACK确认 SACK streams.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());

                } catch (Exception e) {
                    log.error("处理订单异常",e);
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException ex) {
                        ex.printStackTrace();
                    }
                }
            }
        }
    }

    // 线程任务
    /*
    private class VoucherOrderHandler implements Runnable{
        @Override
        public void run() {
            while (true) {
                try {
                    // 1、获取队列中的订单信息
                    VoucherOrder voucherOrder = orderTasks.take();
                    // 2、创建订单
                    handleVoucherOrder(voucherOrder);
                } catch (Exception e) {
                    log.error("处理订单异常",e);
                }
            }
        }
    }
     */

    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        // 获取用户
        Long userId = voucherOrder.getUserId();
        // 创建锁对象
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        // 获取锁
        boolean isLock = lock.tryLock();
        // 判断是否获取锁成功
        if (!isLock) {
            // 获取锁失败，返回错误或重试
            log.error("不允许重复下单");
            return;
        }
        try {
            proxy.createVoucherOrder(voucherOrder);
        } finally {
            // 释放锁
            lock.unlock();
        }
    }

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    private IVoucherOrderService proxy;
    @Override
    public Result seckillVoucher(Long voucherId) {
        // 获取用户 ID
        Long userId = UserHolder.getUser().getId();
        // 订单 id
        Long orderId = redisIdWorker.nextId("order");
        // 1、执行 lua 脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString(),
                String.valueOf(orderId)
        );
        // 2、判断结果是否为0
        int r = result.intValue();
        if (r != 0) {
            // 2.1 不为 0，代表没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        // 3、获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        // 4、返回订单 id
        return Result.ok(orderId);
    }

    /*
    @Override
    public Result seckillVoucher(Long voucherId) {
        // 获取用户 ID
        Long userId = UserHolder.getUser().getId();
        // 1、执行 lua 脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString()
        );
        // 2、判断结果是否为0
        int r = result.intValue();
        if (r != 0) {
            // 2.1 不为 0，代表没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        // 2.2 为0，有购买资格，把下单信息保存到阻塞队列
        VoucherOrder voucherOrder = new VoucherOrder();
        // 2.3 订单 id
        Long orderId = redisIdWorker.nextId("order");
        voucherOrder.setId(orderId);
        // 2.4 用户id
        voucherOrder.setUserId(userId);
        // 2.5 代金卷 id
        voucherOrder.setVoucherId(voucherId);
        // 2.6 创建阻塞队列
        orderTasks.add(voucherOrder);
        // 3、获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        // 4、返回订单 id
        return Result.ok(orderId);
    }
     */

    /*
    @Override
    public Result seckillVoucher(Long voucherId) {
        // 1、查询优惠券
        SeckillVoucher voucher = iSeckillVoucherService.getById(voucherId);
        // 2、判断秒杀是否开始
        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
            // 尚未开始
            return Result.fail("秒杀尚未开始！！");
        }
        // 3、判断秒杀是否结束
        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
            // 已经结束
            return Result.fail("秒杀已经结束！！");
        }
        // 4、判断库存是否充足
        if (voucher.getStock() < 1) {
            // 库存不足
            return Result.fail("库存不足");
        }

        Long userId = UserHolder.getUser().getId();
        // 创建锁对象、
        //SimpleRedisLock lock = new SimpleRedisLock(stringRedisTemplate, "order:" + userId);
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        // 获取锁
        boolean isLock = lock.tryLock();
        // 判断是否获取锁成功
        if (!isLock) {
            // 获取锁失败,返回错误或重试
            return Result.fail("不允许重复下单！！");
        }
        try {
            // 获取代理对象（事务）
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        }finally {
            // 释放锁
            lock.unlock();
        }


    }

     */

    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        // 一人一单
        Long userId = voucherOrder.getUserId();

        // 查询订单
        int count = query().eq("user_id", userId).eq("voucher_id", voucherOrder).count();
        // 判断是否存在
        if (count > 0) {
            // 用户已经买过了
            log.error("用户已经购买过一次了");
            return;
        }

            // 5、扣减库存
            boolean success = iSeckillVoucherService.update()
                    .setSql("stock = stock - 1")
                    .eq("voucher_id", voucherOrder)
                    .gt("stock", 0)
                    .update();
            if (!success) {
                // 扣减失败
                log.error("库存不足！！");
                return;
            }
            save(voucherOrder);
    }
}
